sniff out home; that they are guided by the
stars or the electric impulses of the earth's
magnetic field. No one really knows.
Salmon frolic in estuaries off home rivers,
gradually becoming accustomed to brackish
water before making a run into fresh water.
An old Canadian bush pilot told me of seals
waiting for salmon in the estuary and lower
pools of the Moisie River on the north shore
of the St. Lawrence in Quebec, and how
fancy sportsmen hired Indians to shoot the
seals so that there would be more salmon in
the river for them to catch.
Once in the rivers, salmon may stay the
season just above tidewater or run far in
land, traveling as far as 25 miles in a day.
They are capable of running powerful rap
ids and jumping falls 12 feet high. Often
when I caught them, I found their bodies
badly bruised by this punishing travel. It's a
myth that the very biggest fish, all females,
enter rivers first, but the big females that do
come first, along with the big males, seem to
make long runs. An Atlantic salmon may
run hundreds of miles from the sea to spawn.
As they migrate upriver, each salmon
somehow finds the turnoff to its natal
stream, no matter how many tributaries a
river may have.
Fish Fail to Find New Home
"We sold some fish to a club 60 miles
away, where they were released into the
club's river," Th6r Gudj6nsson, Iceland's
director of freshwater fisheries, recalled one
day. "They went to sea, but after several
days a few showed up here at our hatchery."
He laughed. "The club refused to pay for
those fish, and I couldn't blame them."
Returning Atlantic salmon give up eating
after leaving salt water. In fresh water for as
long as a year, they survive on fat built up on
the feeding grounds at sea. Soon after enter
ing the rivers, they begin to change. Inter
nally, digestive organs shrink to make way
for developing sexual equipment. External
ly, they darken, silver sides turning tannish,
then brown, and their blue or purple backs
become almost black.
Changes are most striking among males,
which develop wicked hooked lower jaws,
called kypes. Shortly before spawning,
males may take on impressive coloration, re
sembling giant brown trout with expansive
608
red and orange blotches on their sides,
splashes of rich yellow on their bellies. Most
fishermen, however, favor them fresh and
silver, because it's then they are most willing
to take a fly, fight hardest, and taste best.
When nights become frosty and water
cools to about 40°F, salmon move at last to
gravel bars to spawn. Spawning occurs from
September to January, depending on the re
gion. Sometimes they make runs upstream,
but often they need only glide to bars nearby
from pools where they were holding.
Before spawning, there's a lot of jockey
ing for position and fighting among females,
called hen fish. The best conditioned usually
claim the best spawning places. Males,
called cocks, have terrific bouts. Some cocks
maneuver well like true boxers, while others
are tough but defensive like good counter
punchers. The most powerful are very ag
gressive, charging and butting until weaker
fish are hurt badly or driven off.
The hens roll on their sides and flutter
their tails in the gravel, making hollowed
out places called redds. There the hens are
joined by males, which wait trembling.
Mating salmon lie side by side, and the fe
males deposit eggs, which are fertilized with
milt, a milky liquid ejaculated by the males.
A hen salmon lays between 700 and 800 eggs
per pound of body weight, and when they
are fertilized, she covers them with gravel.
The cock fish may then go off to serve sever
al other females.
Atlantic salmon, unlike the Pacific vari
eties, which are physiologically determined
to die after spawning, aren't necessarily
used up by the act, though many don't sur
vive long. Some, mostly females, live to
spawn again one or more times, making the
same journey each time. The record is six.
Fish that have spawned are called kelts,
slinks, or black salmon.
In the spring about 60 percent of the eggs
hatch, and the tiny fish, called alevins, re
main in the gravel several weeks, nourished
by their yolk sacs (right). They swim up
when they are about an inch long and begin
to live off the river, first on microscopic or
ganisms and finally on insects and worms.
Young salmon spend several years in the
rivers. Little salmon are first known as fry,
then fingerlings, and finally parr, which is
the longest freshwater stage. Parr look like
NationalGeographic, November 1981